This invention relates generally to turbine engines and, more particularly, to a turbo shaft engine using an acoustical compression flow amplifying ramjet to move a large volume of air across turbine blades with a small volume of high energy air.
Conventional gas turbine engines operate to compress incoming air to increase its pressure before it is ignited in a combustion chamber. High energy exhaust gases exit the combustion chamber to drive a turbine and are then exhausted from the engine. Existing systems, however, suffer from a myriad of design complexities and limitations such as thermal inefficiency, fuel consumption, and performance and material limitations due to intense heat production during operation.
Therefore, it is desirable to have a turbo shaft engine which utilizes a small amount of highly energized air to move a large amount of incoming air across turbine blades. This limited bum decreases typical thermal inefficiencies and limitations. Further, it is desirable to have a turbo shaft engine that extracts energy from both incoming air and energized motive flows. It is also desirable to have turbo shaft engine that utilizes a ramjet which uses acoustical pulses for sequentially staging multiple flow rate amplifications.
An improved turbo shaft engine according to the present invention includes a turbine housing defining an inlet opening for receiving an intake flow into an interior chamber. A turbine assembly having a plurality of blades is rotatably mounted in the chamber for rotation by the intake flow. The turbine housing is coupled to a ramjet gas generator having a tubular primary air duct. The air duct defines opposed intake and outlet ports, the intake port receiving the intake flow from the chamber. The gas generator includes a primary inlet passage configured to receive a portion of the intake flow from the primary air duct, the flow direction of the intake flow portion being reversed by an arcuate wall. This flow reversal increases the pressure or density of the intake flow portion. The gas generator includes a primary combustion chamber positioned to receive the intake flow portion and, upon injection of fuel, to ignite the intake flow portion to form a highly energized motive flow. A portion of the motive flow passes as a back-flash into a resonance chamber and causes acoustical waves that pulsatingly draw more intake flow into the combustion chamber, compress it prior to combustion, and expel motive flow back into the air intake port following combustion. Exhausting the high velocity motive flow back into the primary air duct results in a momentum transfer through direct impact with the slower moving intake flow. The air discharged back into the primary air duct may be directed along a discharge guide member having a Coanda profile for efficient mixing. Thus, a large volume of air is moved toward the outlet port using a small volume of high energy air (motive flow). This sequential amplification of intake air is performed efficiently due to the acoustical pulse within the resonance chamber. Flow amplification increases mass air flow and primary fuel combustion efficiency.
A motive flow and a majority of the intake flow are diffused into a secondary combustion chamber for a limited bum combustion. This combustion is accomplished efficiently and with a limited amount of fuel in that the secondary combustion chamber is configured to induce a torroidal vortex during combustion. A majority of the amplified motive flow is passed through an exhaust adapter coupled to the turbine blower housing for rotation of the turbine blades. As the amplified motive flow passes over the blades, it is centrifugally discharged into the atmosphere through an outlet opening.
Therefore, a general object of this invention is to provide an improved turbo shaft engine which moves a large amount of air using a small amount of high energy air.
Another object of this invention is to provide a turbo shaft engine, as aforesaid, which amplifies the energy of an air intake flow through momentum transfer provided by a motive flow reintroduced into a primary air duct following combustion.
Still another object of this invention is to provide a turbo shaft engine, as aforesaid, which extracts energy from the velocity of incoming air for improving low RPM torque output.
Yet another object of this invention is to provide a turbo shaft engine, as aforesaid, which reduces thermal inefficiency by utilizing limited combustion and self-cooling with incoming air.
A further object of this invention is to provide a turbo shaft engine, as aforesaid, which lowers nitrous oxide and other pollutant emissions.
A still further object of this invention is to provide a turbo shaft engine, as aforesaid, which utilizes an acoustical pulse for pumping and compressing an intake air flow into a primary combustion chamber.
A particular object of this invention is to provide a turbo shaft engine, as aforesaid, in which the acoustical pulse for pumping and compressing may be adjusted or tuned by a user.
Another object of this invention is to provide a turbo shaft engine, as aforesaid, in which the discharge of the motive flow back into the primary air duct is efficiently mixed according to a Coanda effect.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, embodiments of this invention.